Non-ISSI LMR to LTE MCPTTDon Bradshaw, PSCR // Chris Walton, PSCR

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#PSCR2019

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DISCLAIMER

Certain commercial entities, equipment, or materials may be identified in this document in order to describe an

experimental procedure or concept adequately. Such identification is not intended to imply

recommendation or endorsement by the National Institute of Standards and Technology, nor is it intended

to imply that the entities, materials, or equipment are necessarily the best available for the purpose.

*Please note, unless mentioned in reference to a NIST Publication, all information and data presented is

preliminary/in-progress and subject to change

Executive Summary

• Status of LMR to LTE Capabilities and Development• The Missing Combination• PSCR’s LMR to LTE Strategy• Recognized Challenges• Current Research Project• Success

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Status of LMR to LTE Capabilities and Development

• Inter-RF Subsystem Interface (ISSI)• Designed for P25 to P25 System Interoperability• Focus of Government and Industry for LMR to LTE• Solution for Compatible Systems (Newer P25)• 3GPP Interface Compliant Through Interworking Function (IWF)

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LMRBase Station

ISSI IWFMCPTT

AppServer

LTECore/RAN

Status of LMR to LTE Capabilities and Development

• Bridging System Interfaces (Radio Over IP <ROIP>)• Originally Designed for non-ISSI LMR Systems• Requires Donor Radios or System Level Connection• Proprietary Interfaces

• May Include 3GPP IWF (DHS Small Business Innovation Research) Interface

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LMRRepeater

BSIMCPTT

AppServer

LTECore/RAN

DonorRadio Proprietary

Proprietary

Proprietary

Status of LMR to LTE Capabilities and Development

• Custom Solutions• LMR Infrastructure to LTE App• Do Not Inherently Function on LTE Devices

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LMRBase Station

CustomLMR

Interface

MCPTTApp

Server

LTECore/RAN

OTTAPP

CustomLTE

Interface

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The Missing Combination

• Air-Interface (RF) Based• Does Not Require Special Interface to Existing Systems

• Affordable• No Donor Radios Required

• 3GPP Standards-Based• Compatible with IWF and Mission Critical Push-to-Talk (MCPTT) Servers• Does Not Require Middleware Service• No Special Apps

• Open Source• Competitive Environment for Companies

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PSCR’s LMR to LTE Strategy

• Overall Goal: Fill the Technology Gaps• ISSI is Being Addressed by Industry• ROIP and Other Custom Solutions Exist

• Timeframe• Full LMR to LTE Effort

• Two to Three Years• Current Project

• Six Months

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PSCR’s LMR to LTE Strategy

• Research Objectives• Research and Prototype Software Defined Radio (SDR) Solutions

• “LTE core talks to the tower like it’s a radio”• Focus on analog FM and non-ISSI compatible P25

• Determine if Existing IWF and MCPTT Capabilities Are Sufficient• Target Efforts to Fill Gaps

• 3GPP Standards Involvement and Contributions• Position Industry to Benefit Public Safety

LMRRepeater

IWFMCPTT

AppServer

LTECore/RANSDR

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Recognized Challenges

• Voice Encryption• Security• Usability• Adoption of Products by Cellular Providers• Adoption by 3GPP

Current Research ProjectInnovative and affordable interworking of analog FM LMR radios in the LTE MCPTT world

Chris Walton, PSCR

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Current Research ProjectLMR to LTE Research Project

• Research the integration of analog FM LMR radios into a MCPTT solution via 3GPP IWF.• Leverage existing technologies for a highly standardized

solution. Investigate using SDR (Software Defined Radios via GNU Radio).• Feedback to the standards bodies.

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Current Research ProjectTarget Architecture

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SIP – Session Initiation Protocol• Signaling protocol for session control• Enables audio and video services

• VOIP• VoLTE• MCPTT

RTP – Real Time Transport Protocol• Paired with SIP and RTCP • Transports digitized audio, video

• VOIP• VoLTE• MCPTT

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Current Research ProjectCurrent Milestones

• SDR development of an analog FM receiver• Implementation of basic audio and

in-band signaling• Ability to initiate SIP based VoIP

calls in a scripted testing environment• Voice pass thru from the analog

LMR to a LTE UE

Accomplishments (to date)

Next Steps• Development of a standards-

compliant media plane control to handle floor control across platforms• Drive toward R16 IWF compliant

solution • Research co-existence and/or

integration with ISSI

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Current Research ProjectChallenges – Standards publication across various bodies

• LTE• 3GPP – 3rd Generation Partnership Project

• Stage 3 R16 work (Jun19)

• P25 • TIA – Telecommunications Industry Association • ATIS – Alliance for Telecommunications Solutions

• Study on Interworking P25 LMR – MCPTT (Jun19)• Base on R15 IWF

• ETSI• ETSI – European Telecommunications Standards Institute

• TCCE (TETRA and Critical Communications Evolution) WG4• Complete work AFTER 3GPP R16 is published• Will be used by TIA and 3GPP to update future standards

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Success

• Publicly Available Technology for Non-ISSI Legacy LMR to LTE• Integration and Testing of a Prototype System • Bridge PSCR LMR and LTE test beds

• Use of Open Source Software Solutions • Low cost and enduring solution

• Use of Software Defined Radios • No Donor Radios

• Technology and Path for Companies to Develop Products• 3GPP Compliance and Support

THANK YOU

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Get your hands on the tech!

Demos OpenBACK TOMORROW

8:00 AM

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